The present invention relates to an X-ray fluoroscopic imaging apparatus for examining an object to be examined by taking fluoroscopic images.
2. Description of the Background Art
Several types of an X-ray fluoroscopic imaging apparatus are known conventionally.
One example of such a conventional X-ray fluoroscopic imaging apparatus is shown in FIG. 1, where an X-ray fluoroscopic imaging apparatus 1 is equipped with an approximately C-shaped supporting arm 2 which carries a fluoroscopic imaging device and an X-ray tube on its two opening ends. This C-shaped supporting arm 2 can slide along a circle centered around an isocenter O, in a direction indicated by an arrow A. A stem of this C-shaped arm is supported to be rotatable in a vertical plane, in a direction indicated by an arrow B, by a supporting base 3 attached to a floor. The supporting base 3 itself is also rotatable in a direction indicated by an arrow C in a horizontal plane.
Another example of such a conventional X-ray fluoroscopic imaging apparatus is shown in FIG. 2, where the X-ray fluoroscopic imaging apparatus 4 is equipped with an approximately U-shaped supporting arm 5 which carries a fluoroscopic imaging device and an X-ray tube on its two opening ends. Two legs of this U-shaped supporting arm 5 can reciprocatively slide as indicated by arrows D such that an isocenter O remains on a line joining the fluoroscopic imaging device and the X-ray tube on two opening ends. A stem of this U-shaped arm 4 is supported to be rotatable in a vertical plane, in a direction indicated by an arrow E, by a supporting base 6 attached to a floor.
Still another example of such a conventional X-ray fluoroscopic imaging apparatus is shown in FIG. 3, which differs from the example of FIG. 1 in that, in this conventional X-ray fluoroscopic imaging apparatus 7, the supporting base 9 for supporting the C-shaped arm 8 is attached not to the floor but to the ceiling.
Now, all of these conventional X-ray fluoroscopic imaging apparatus have a problem that, in taking an image of a heart of a patient for instance, due to the lack of enough degrees of freedom for its arm carrying the fluoroscopic imaging device and the X-ray tube, it has been impossible to obtain the X-ray fluoroscopic images from all directions around a region of interest in the object to be examined located at the isocenter O, without changing a position or an orientation of the object to be examined itself.
On the other hand, when the object to be examined is moved to change its position, overlapping of the images before and after the moving occurs on a display, for example for the images of blood vessels, whereas when the object to be examined is moved to change its orientation, a displayed image on a monitor is rotated, and these can give rise to difficulties or errors in the diagnosis using the displayed image.
Moreover, in taking an image of blood vessels in an inferior limb of a patient, because the image cannot be taken completely by a single imaging operation at a single position, it is inevitably necessary to shift the imaging region gradually for several times in a course of successive imaging operations, and in such a case, it has been unavoidable conventionally to move the patient for each imaging, which causes the similar problem associated with the moving of the patient as mentioned above.